A solid oxide fuel cell (hereinafter referred to as the “SOFC”) includes a solid electrolyte-electrode laminate in which a fuel electrode and an air electrode are disposed on both sides of a solid electrolyte layer.
As materials constituting the solid electrolyte layer in the SOFC, yttrium doped barium cerate (hereinafter referred to as “BCY”) and yttrium doped barium zirconate (hereinafter referred to as “BZY”), which are perovskite-type oxides, are known. The solid oxides have good proton conductivity at low to medium temperatures, not higher than 700° C., and therefore are considered as promising electrode materials for SOFCs operated at low to medium temperatures.
The fuel electrode of the SOFC is typically formed by adding a catalyst component to the solid oxide constituting the solid electrolyte layer. A noble metal such as platinum is used as the catalyst component, which gives rise to a problem of increased production costs. In order to avoid the problem, it is possible to use inexpensive nickel (Ni) as a catalyst.
Furthermore, in order to decrease the ionic conductivity resistance in the solid electrolyte layer, it is desirable to decrease the thickness of the solid electrolyte layer as much as possible. However, when the solid electrolyte layer is thinly formed, the strength of the solid electrolyte layer is decreased, which causes problems in the production process and during use. Accordingly, in many cases, a solid electrolyte-electrode laminate having a structure (anode support structure), in which a solid electrolyte layer is formed on a surface of a thickly formed fuel electrode so as to secure the strength as the laminate, is employed.
In order to produce the solid electrolyte-electrode laminate, a method may be employed, in which solid electrolyte powder is thinly applied onto a fuel electrode powder molded body, the resulting laminate is fired to integrally form a solid electrolyte-fuel electrode laminate, and then an air electrode is formed thereon.
PTL 1: Japanese Unexamined Patent Application Publication No. 2005-19041